1. Field of the Invention
The present invention relates to an apparatus connected to a network, and an address determination program and method.
2. Description of the Related Art
With the remarkable progress of communications on the Internet, conventional network-capable equipment has been developed into various network-capable appliances such as not only conventional personal computers but also user interactive devices including PDA (personal digital assistance), mobile telephones, etc., image processing devices including scanners, printers, copying machines, digital cameras, etc., and household electric appliances including televisions, air-conditioners, refrigerators, etc.
Correspondingly, the procedure for a network connection of a network-capable equipment conventionally used by a network manager has been simplified. Especially, relating to setting an IP address which is very important in setting an Internet protocol (IP), the conventional manual setting process has been replaced with a newly suggested automatic IP address assigning process using a DHCP (dynamic host configuration protocol) server, or an automatic IP address acquiring process (draft-ietf-zeroconf-ipv4-linklocal-01.txt) suggested for a SOHO (small office/home office) environment, that is, a network environment in which a server cannot be mounted. In the Universal Plug and Play Device Architecture v1.0 presented by Microsoft Corporation, the above mentioned automatic IP address acquiring process is adopted. Thus, the common users can use the above mentioned network-capable equipment without consideration of the setting regulations and the management of an IP address, etc.
However, there have been the following problems with the above mentioned conventional technology.
That is, if a network-capable device implements an algorithm for acquiring an IP address as recommended in the above mentioned automatic IP address acquiring process (draft-ietf-zeroconf-ipv4-linklocal-01.txt), then the network-capable device performs a process of acquiring a new IP address upon start-up. However, if a number of devices simultaneously start up every morning or immediately after a failure such as a power failure, etc. occurs or in the environment of several tens of units of network-capable equipment connected to a network, then there occurs network traffic by an ARP (address resolution protocol) packets for check of addresses on the network, and there can occur a conflict for IP addresses depending on the settings of waiting time for a ARP response.
Furthermore, if there are no dynamic DNS (domain name service, which is a distribution directory management system for Internet, for associating an IP address with a domain name) in the network, then a client who uses the network-capable service has to establish communications using an IP address not a host name. Therefore, each time the IP address of the network-capable device is changed, it is necessary also change the settings of the client application.